Tyler O'Neill

In 2019, O'Neill made St. Louis' Opening Day roster, but his season was interrupted by injuries alongside being reassigned to Memphis for over a month. He was recalled to St. Louis in June, and finished the year with them. Over sixty games, he hit .262 with five home runs and 16 RBIs.

MLB.com ranked O'Neill as St Louis' fourth best prospect going into the 2018 season. He competed in spring training for an opportunity to make the major league roster as a reserve, but hamstring and oblique injuries kept him out of play. He began the season with Memphis and was promoted to the major leagues on April 19, 2018. He had been leading the PCL with six home runs and 18 RBI. He made his debut the next night at Wrigley Field against the Chicago Cubs, making him the sixth Canadian-born player to appear on an active major league roster on the season. He was sent back down on April 28 after seven hitless at bats and recalled again on May 18. He mustered his first major league hit, a single off Yacksel Ríos of the Philadelphia Phillies that same night in a 12–4 St. Louis win. O'Neill hit his first major league home run the next day off Luis García. On May 21, he amassed his first four-RBI game, and homered in his third consecutive game the following day. He was optioned back to Memphis on May 31 and was recalled by St. Louis for the second time on July 2 to take the spot of Dexter Fowler, who had gone on paternity leave. He was placed on the 10-day disabled list on July 5 with a hamstring strain, was activated on June 17, and was optioned back to Memphis. He was recalled once again on July 31 following the trade of Tommy Pham, and spent the remainder of the season in St. Louis. He hit his first walk-off home run on September 22, a 414-foot shot, against the San Francisco Giants, leading St. Louis to a 5-4 victory. In 61 games for the Cardinals, O'Neill batted .254 with nine home runs and 23 RBIs.

From the Greater Vancouver area of British Columbia, the Seattle Mariners selected O'Neill in the third round of the 2013 amateur draft. In 2016, he was the Southern League Most Valuable Player (MVP) along with winning the Southern League championship with the Jackson Generals. On July 21, 2017, the Mariners traded him to the Cardinals. Later that year, he won the Pacific Coast League championship as a member of the Memphis Redbirds.

On July 21, 2017, the St. Louis Cardinals acquired O'Neill for pitcher Marco Gonzales, and assigned him to the Memphis Redbirds of the PCL.

O'Neill finished 2017 with a combined .246 batting average, 31 home runs, and 95 RBIs in 130 games between Tacoma and Memphis. The Redbirds became the 2017 PCL champions after defeating the El Paso Chihuahuas in five games in the league championship final, giving O'Neill consecutive minor league championships with two different organizations at two different levels. The Cardinals added him to their 40-man roster after the season to protect him from being chosen in the Rule 5 Draft.

O'Neill plays the piano, and entertained his teammates in the clubhouse during spring training in 2017 by playing the theme song to the "Lord of the Rings" film series on a keyboard. He says his favourite song to play is "O Canada."

He spent 2016 with the Jackson Generals of the Southern League, where he batted .293 with 24 home runs and 102 RBIs. Jackson won the Southern League championship after a league best 84–55 record, and O'Neill was the Southern League Most Valuable Player (MVP). In seven playoff contests, he batted .448, three home runs and eight RBIs. He began 2017 with the Tacoma Rainers of the Class AAA Pacific Coast League (PCL).

The Seattle Mariners selected O'Neill in the third round of the 2013 Major League Baseball draft. He signed with the Mariners and made his professional debut with the Arizona League Mariners. In 2014, O'Neill played in only 51 games between the Arizona League Mariners, Everett AquaSox and Clinton LumberKings due to a broken bone in his right hand he suffered after punching a concrete wall in the dugout. He spent 2015 with the Bakersfield Blaze, where he posted a .260 batting average to go along with 32 home runs and 87 RBIs. O'Neill played for the Canada national team at the 2015 Pan American games in Toronto and the 2015 WBSC Premier12. In the 2015 Pan Am Games final, Canada defeated the United States 7–6 in extra innings to claim the gold medal.

Tyler Alan O'Neill (born June 22, 1995) is a Canadian professional baseball outfielder for the St. Louis Cardinals of Major League Baseball (MLB). He made his major league debut on April 19, 2018. He has represented Canada in international play, winning a gold medal at the 2015 Pan American games. O'Neill stands 5 feet 11 inches (1.80 m) tall, weighs 210 pounds (95 kg), and throws and bats right-handed.

O'Neill's father, Terry, was named Mr. Canada (an honor given to the nation's best body builder) in 1975.